1. Field of the Invention
The invention generally relates to devices and related methods for treating intracardiac defects. More particularly, the invention provides an intracardiac occluder with a biological tissue scaffold, and related methods, for the percutaneous closure of intracardiac defects.
2. Background Information
The human heart is divided into four compartments or chambers. The left and right atria are located in the upper portion of the heart and the left and right ventricles are located in the lower portion of the heart. The left and right atria are separated from each other by a muscular wall, the intraatrial septum, while the ventricles are separated by the intraventricular septum.
Either congenitally or by acquisition, abnormal openings, holes, or shunts can occur between the chambers of the heart or the great vessels, causing blood to flow therethrough. Such deformities are usually congenital and originate during fetal life when the heart forms from a folded tube into a four chambered, two unit system. The deformities result from the incomplete formation of the septum, or muscular wall, between the chambers of the heart and can cause significant problems. Ultimately, the deformities add strain on the heart, which may result in heart failure if they are not corrected.
One such deformity or defect, a patent foramen ovale, is a persistent, one-way, usually flap-like opening in the wall between the right atrium and left atrium of the heart. Since left atrial pressure is normally higher than right atrial pressure, the flap typically stays closed. Under certain conditions, however, right atrial pressure exceeds left atrial pressure, creating the possibility for right to left shunting that can allow blood clots to enter the systemic circulation. This is particularly worrisome to patients who are prone to forming venous thrombus, such as those with deep vein thrombosis or clotting abnormalities.
Nonsurgical (i.e., percutaneous) closure of patent foramen ovales, as well as similar intracardiac defects such as atrial septal defects, ventricular septal defects, and left atrial appendages, is possible using a variety of mechanical closure devices. These devices, which allow patients to avoid the potential side effects often associated with standard anticoagulation therapies, typically consist of a metallic structural framework that is combined with a synthetic scaffold material. The synthetic scaffold material encourages ingrowth and encapsulation of the device. Current devices typically utilize a polyester fabric, expanded polytetrafluoroethylene (ePTFE), Ivalon®, or a metal mesh as the synthetic scaffold material. Such devices suffer, however, from several disadvantages, including thrombus formation, chronic inflammation, and residual leaks.